Acoustophoretic printing apparatus and method

Abstract

The present invention contains a printing apparatus and a method, e.g., for ejecting inks (i.e., pure liquids, mixtures, colloids, etc.) for a very broad range of physical properties (such as viscosity). Acoustic forces 3 a may be generated by an emitter 1 and a reflector 2 to detach droplets 10 from a nozzle 6 . The ink may be advanced through the nozzle 6 by a standard back pressure system 5 . A reflectorless chamber 7 may enhance acoustic forces 8 a and the droplets 10 may be ejected at a bottom 9 of said chamber 7 , so that droplets 10 may be deposited on any substrate 11.

The invention claimed is: 
     
       1. A printing apparatus comprising:
 an emitter arranged within a first fluid and configured to oscillate for generating an acoustic field in the first fluid; 
 a nozzle with a nozzle opening placed at a predetermined position within the acoustic field; and 
 a second fluid within the nozzle, 
 wherein the nozzle is connected to a tubing for a fluidic connection between a second fluid reservoir and the nozzle opening. 
 
     
     
       2. The printing apparatus of  claim 1  comprising:
 wherein the tubing has a diameter ranging from 0.1 μm to several centimeters. 
 
     
     
       3. The printing apparatus of  claim 1 , wherein the nozzle comprises a tapered glass capillary, a metallic tube, a Teflon capillary or a microfabricated tube. 
     
     
       4. The printing apparatus of  claim 1 , wherein the nozzle opening comprises a hydrophobic treatment to reduce wetting by the second fluid. 
     
     
       5. The printing apparatus of  claim 1 , wherein the nozzle opening is positioned in opposition to a printing substrate. 
     
     
       6. The printing apparatus of  claim 1 , wherein the tubing is bent, the nozzle being introduced from a side wall or side surface of the printing apparatus. 
     
     
       7. The printing apparatus of  claim 1 , wherein the emitter is attached to or includes a piezoelectric transducer or a magnetostrictive transducer. 
     
     
       8. A printing apparatus comprising:
 an emitter arranged within a first fluid and configured to oscillate for generating an acoustic field in the first fluid; 
 a nozzle with a nozzle opening placed at a predetermined position within the acoustic field; and 
 a second fluid within the nozzle, 
 wherein the nozzle is introduced from a side wall or side surface of the printing apparatus. 
 
     
     
       9. The printing apparatus of  claim 8 , wherein the nozzle is connected to tubing for a fluidic connection between a second fluid reservoir and the nozzle opening. 
     
     
       10. The printing apparatus of  claim 9 , wherein the tubing is bent. 
     
     
       11. The printing apparatus of  claim 8 , wherein the nozzle comprises a tapered glass capillary, a metallic tube, a Teflon capillary or a microfabricated tube. 
     
     
       12. The printing apparatus of  claim 8 , wherein the nozzle opening comprises a hydrophobic treatment to reduce wetting by the second fluid. 
     
     
       13. The printing apparatus of  claim 8 , wherein the nozzle opening is positioned in opposition to a printing substrate. 
     
     
       14. The printing apparatus of  claim 8 , wherein the emitter is attached to or includes a piezoelectric transducer or a magnetostrictive transducer. 
     
     
       15. A method of acoustophoretic printing, the method comprising:
 arranging a nozzle within a first fluid; 
 generating an acoustic field in the first fluid by an oscillating emitter; and 
 driving a second fluid out of the nozzle, thereby forming a pendant droplet of the second fluid at the nozzle opening, wherein acoustic forces from the acoustic field promote detachment of the pendant droplet from the nozzle opening, 
 wherein oscillation of the oscillating emitter is set constant or is modulated. 
 
     
     
       16. The method of  claim 15 , wherein the modulation of the oscillation comprises changing the oscillation frequency, phase and/or amplitude. 
     
     
       17. The method of  claim 15 , wherein the first fluid comprises air and the second fluid comprises a liquid selected from the group consisting of: water, an ink/dispersion, a pure liquid, a mixture, a colloid, and a liquid metal. 
     
     
       18. The method of  claim 15 , wherein the oscillating emitter has an oscillation frequency in a range from 1 Hz to 1 GHz. 
     
     
       19. The method of  claim 15 , wherein the nozzle has a nozzle opening positioned in opposition to a printing substrate, and
 wherein, upon detachment of the pendant droplet from the nozzle opening, the second fluid is deposited onto the printing substrate as a printed droplet. 
 
     
     
       20. The method of  claim 15 , wherein the nozzle is introduced from a side wall or side surface of the printing apparatus.